Which is an incision into the thin connective tissue sheet that wraps around each individual muscle or a group of muscles?

The answer is fasciotomy

Fascio - from fascia
-tomy - means to cut.

The thin layer of connective tissue mentioned is called the fascia. It is attached to the individual muscle or muscle groups. It encloses the muscle/muscle groups to stabilize and separate them.

A fasciotomy is a procedure where the fascia of an affected area is cut to relieve pressure or tension build up. 

The answer is c) tons